Build times will depend on difficulty level, map type, and the AIs in the game so without at least knowing the first two, it's impossible to give dates.
On prince, with a decent start, you can almost be guaranteed one of the 6 ancient wonders. You can probably get 3-4 if you make them a priority, but IMO you're going to slow yourself down trying and make later wonders that would be yours to take (because of tech/production superiority) competitive at least. Of the 6, 2 require you open a policy tree: liberty for the pyramids and honor for the Statue of Zeus. Opening multiple social policy trees just for the wonders is generally bad so unless you plan to pick these anyway, I would probably skip the associated wonders. SoZ is nice if you're doing an early domination victory, but if you're being peaceful it's fairly worthless. You can get a bigger bonus by teching faster and having stronger units. For the pyramids, you can buy 2.5 workers for the same price so I'm not a big fan. Getting 1 worker out in < half the time will more than make up for the loss of the +25% tile improvement rate.
For the other ancients, the Great Library is probably the one most people would take given the choice. +3 science is a lot at that point, and if you time it right to get a tech that would normally take 15 turns to research, that can be huge. Stonehenge is great if you want to found a religion. Both these are also on the way to philosophy (for the national college) so I'm usually researching the techs. These are probably #1 and #2 in my games if I get 2 ancient wonders. Temple of Artemis has some decent bonuses, but it comes very early in the tech tree which makes it probably the easiest to lose out on. Even on Prince, an AI could pop archery on turn 1 and start building immediately. The mausoleum seems OK, but unless I had several stone/marble in my city I wouldn't bother.
For the classical, I think the Hanging Gardens is awesome on almost any game, and I usually take it unless I'm not doing tradition (which is the most generally useful policy tree on most games). If you have lots of desert tiles in the city, you absolutely want Petra since it makes them useful. Colossus can be quite strong if you have a coastal city, and if you have lots of water on the map, the Great Lighthouse is great. The free policy of the oracle is great, and since teching to philosophy early is a common strategy, this is useful. The Parthenon's culture is nice, but I usually value it pretty low unless I want a cultural victory. Terracotta Army is the weakest classical wonder IMO. It costs 250h, and you only get one of each unit type. Typically this might be 1 scout, 1 warrior, 1 archer, 1 spear, and 1 horse, which cost less than the wonder. 250h is 6 archers for example, almost 5 composite bows, or 3.5 swords/spears.
For medieval and later wonders, you're probably better to select based on the tech path you want to pursue or what you really need (e.g., Hagia/Great Mosque to help with religion, etc.) This advice really applies to all eras, but the bonuses aren't as huge, relative to your whole empire, as the ancient/classical ones can be. If you're playing well (assuming ~Prince difficulty) you can probably double back and still get a lot of these anyway since you'll be pulling away in techs. You don't want to give up too much trying to grab every wonder. Building 2-3 archers, a worker, settler, granary, etc may help you more in the long run than another wonder.